Electrical connectors are commonly used to terminate electrical cords for various electrical and electronic appliances with the connector typically having male prongs for insertion into a female receptacle to thereby connect and disconnect the electrical appliance from a suitable power source. Additionally, electrical connectors are also used with devices such as battery chargers to terminate electrical cables which carry the charging current so that the connector may be readily inserted into a female receptacle which is electrically in circuit with one or more batteries desired to be recharged. One such particular application is for electrically powered golf carts commonly used on most golf courses. In these particular applications, the golf cart has a female connector which facilitates the recharging of the battery overnight after a full day's usage on the golf links. These female receptacles are generally provided with spring tension contact clips into which the male blades of the electrical plug are inserted in order to complete the electrical connection therebetween. Because of the charging currents utilized, it is not uncommon for the blade and spring clips to heat as the charging current is conducted therethrough. Over time, this temperature rise takes the temper out of the brass spring clips which, along with the natural tendency of the clips to "loosen" as a result of the repetitive insertion and removal of the male connector, further weakens the contact pressure between the blade and clips to thereby create an ever worsening cycle of increased temperature during the charging procedure. Because the case of the electrical connector surrounds the male blades, the case being typically made from any hardened plastic such as bakelite or the like, the connector itself may overheat and fail and, in extreme situations, even cause a fire. This is especially a risk when the golf carts are left unattended overnight as they are charged.
Electrical connectors of the kind described herein are typically used to terminate electrical cables substantially larger than is used in most consumer applications. As a result, it is well-known in the art to utilize strain reliefs at the juncture between the electrical connectors and the cable end, those strain reliefs serving not only to mechanically reinforce the juncture, but also restrict the radius about which the cable may be bent and also help minimize the possibility for mechanical damage resulting from an operator tugging on the cord to remove the connector from the receptacle. Typically, in the prior art, clam-shell type electrical connectors were utilized, these clam-shell type connectors being comprised essentially of two halves which are split along the length of the electrical connector, with the strain relief being captured between these two halves and with one or more screws or the like used to join the halves. Unfortunately, with this particular construction, there is a tendency for the connector to "clam-shell" or separate at the point where the strain relief is mounted due to the excessive mechanical forces caused at that juncture by abuse and improper use of the connector and cable by an operator. When this happens, it is not uncommon for the connector and cable to mechanically separate thereby causing a failure. In some cases, this mechanical difficulty can also lead to a hidden weakening or separation of the electrical connections contained within the connector which might lead to increased heating and also further create the possibility for a catastrophic failure such as a short circuit or open circuit condition within the connector, or even a fire.
In order to solve these and other problems in the prior art, the inventor herein has succeeded in designing and developing an electrical connector with an integral mount for a strain relief as well as an overtemperature indicator which senses an overtemperature condition and provides a visual indication to an operator that an overtemperature condition has occurred even after the charging current supplied by the battery charger has been automatically terminated. The electrical connector of the present invention is essentially of clam-shell construction except that at the cable end thereof, one of the connector halves includes as an integral part thereof an end plate with a hole therethrough for anchoring of a strain relief. The end plate is integral and uninterrupted about the hole such that the tendency for the connector to "clam-shell" is eliminated. In this orientation significantly greater mechanical stresses are readily accommodated and do not result in damage to the connector or to the possible separation of the electrical connections within the connector.
Within the interior of the connector, there is mounted a miniature P.C. board and an electronic circuit thereon including a thermistor for sensing a temperature rise above a pre-selected "overtemperature" value which fires a PUT or SCR which illuminates an LED and is latched on so long as the electrical connector remains plugged into the receptacle, thereby being in circuit with the batteries mounted on board the golf cart. This LED is of relatively small size and extends through a small opening in the connector case. Thus, should an overtemperature condition occur, an operator may readily observe the LED being illuminated before the connector is finally disconnected from the golf cart prior to its use, even though the charging cycle may have been completed some hours previously and the connector has had time to cool to ambient temperature. The operator is then in a position to inspect the female receptacle for deterioration of the contact springs and their replacement, or other correction of the situation which caused the overtemperature condition. As can be appreciated, this provides a significant advantage and improvement over the prior art in that it greatly enhances the safety of the charging process which is generally performed without constant supervision, in unattended areas, and for significant time periods.
While the principle advantages and features of the present invention have been described briefly above, a greater understanding and fuller appreciation for the invention may be obtained by referring to the drawings and preferred embodiment which follow.